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Hi, and welcome to COVID Quickly, a scientific American podcast series.

This is your fast track update on the COVID pandemic.

We bring you up to speed on the science behind the most urgent questions about the virus and the disease.

We demystify the research and help you understand what it really means.

I'm Tony Lewis. I'm Josh Fishman.

And we're scientific Americans, senior health editors.

Today, we're talking about whether people need vaccine booster shots.

Also, now that your boss has reopened your office, how to tell if it's COVID safe.

Plus, some things you can do to make it safer.

This week Pfizer, which makes a very effective two-shot vaccine,

met with US officials to say that a third shot of booster might be needed.

Health officials say it isn't yet.

So a lot of people, including me, are confused. Help me out, Tonya.

It is confusing. Pfizer caused quite a stir when it announced it was applying for emergency use authorization for a third booster shot.

Claiming the decision was based on its own data on waning antibody levels over time,

as well as data on breakthrough infections in Israel.

But the FDA and CDC responded quickly, putting out a statement saying that booster shots were not needed yet,

and that they would need to see more data before saying whether and when we might need more shots.

...